Although this invention is being disclosed in connection with cervical cancer, it is applicable to many other areas of medicine and other fields. Diagnosing cervical cancer in women is a multi-step procedure involving examination of the cervix, possible biopsy and follow-up (D. G. Ferris, J. T. Cox, D. M. O'Connor, V. C. Wright, and J. Foerster, Modern Colposcopy. Textbook and Atlas, pp. 1-699, American Society for Colposcopy and Cervical Pathology, 2004; 2. E. Burghardt, H. Pickel, and F. Girardi, Colposcopy—Cervical Pathology, Textbook and Atlas, Thieme, New York, 1998, both incorporated herein by reference). It is open to subjective interpretation and dependent upon the skills of cytologists, colposcopists, and pathologists. In a standard colposcopic examination a colposcopist uses a colposcope, which is a low-power, binocular microscope, to visually examine the cervix at a working distance of approximately 300 mm (0.3 cm). Most colposcopes are not digital and do not record images, and records are conventionally kept as hand-drawn representations. While this hand-drawn representation of the cervix is far from adequate, the drawing does provide a limited reference point from which to compare the status of the cervix in future examinations. A significant improvement over the hand-drawing of the cervix would be the use of a video colposcope, or a colposcope with an attached camera, which can capture and provide an image of the cervix.
A colposcopic-directed biopsy is considered the gold standard for diagnosing cervical pre-cancers and cancer, even though it is a subjective assessment with the range of the positive predicted value of colposcopic-directed biopsies being between 36-63% (J. T. Cox, M. Schiffman, and D. Solomon, “Prospective follow-up suggests similar risk of subsequent cervical intraepithelial neoplasia grade 2 or 3 among women with cervical intraepithelial neoplasia grade 1 or negative colposcopy and directed biopsy”, American Journal of Obstetrics and Gynecology 188, pp. 1406-1412, 2003, incorporated herein by reference).
Colposcopists are trained to differentiate normal from abnormal tissue with the results of their examination based on their experience and training. Among the cues the colposcopist is looking for are the level of whiteness on the cervix and presence of abnormal blood vessels. The standard procedure is to obtain a specimen sample, via biopsy, from those areas having the highest level of perceived abnormality. These biopsies are then sent for further pathological review. An often undesired result is “false positives,” so that unnecessary biopsies are acquired and the specimen is determined normal, which increases the risk of infection, bleeding, physical and emotional discomfort and cost. Furthermore, the decision to treat the patient is based on colposcopic-guided histopathology diagnosis and women with high-grade cervical intraepithelial neoplasia will be referred for more invasive treatment.
In the current practice, biopsies are reviewed by a pathologist, and an overall gross diagnosis of the entire specimen is reported based on the highest level of disease seen. Upon receipt of the pathology report, the colposcopist will know the highest level of disease in the region sampled by the biopsy, not the exact location of the disease within the tissue specimen. Therefore, it is not possible to pinpoint the exact location on the cervix of the reported pathology.
In an effort to reduce the subjective nature of the colposcopist-directed biopsy, and to improve the diagnostic accuracy of colposcopy, new colposcopic imaging systems with accompanying computer aided diagnostic techniques are being developed (as described in co-pending, commonly assigned U.S. patent application Ser. No. 11/895,150, entitled “Uterine Cervical Cancer Computer-Aided Diagnosis (CAD)”, filed Feb. 3, 2005, and Ser. No. 12/291,890, entitled “High Resolution Digital Video Colposcope with Built-In Polarized LED Illumination and Computerized Clinical Data Management System”, filed Nov. 14, 2008, both incorporated herein by reference) to guide a colposcopist in deciding if and where to biopsy. If the biopsy's histopathology (the identification of the disease state at the cellular and near-cellular level), is to be used as the gold standard for computer aided detection systems, then the location of the histopathology analysis must match exactly to the location of the biopsy tissue in the digital image. Otherwise, no matter how perfect the histopathology and the quality of the digital imagery, the two data sets cannot be matched and the true sensitivity and specificity of the computer aided detection system cannot be determined. In addition, by relying on digital imagery accompanied with the exact location of the histopathologic analysis (instead of hand-drawings of the cervix), the colposcopist is provided with a tool that can reduce the subjective nature of the exam and provide detailed reference data from which to compare the status of the cervix in future examinations.
The present invention includes acquisition, processing, and registration techniques that maintain the spatial orientation at each level of tissue processing of a three-dimensional tissue specimen removed from an area of investigation, perform detailed histopathology analysis, and precisely map the location of the histopathology analysis back to a digital image of the area of investigation (registration) acquired prior to removing the tissue specimen. This is accomplished by utilizing tissue image acquisition, processing, and registration technology in combination with mechanical and image processing tools and novel tissue processing procedures.
The tools and procedures are applied both to the digital image and the actual tissue specimens that are removed. One tool, the macrotome, adds precision to the orientation and overall size of tissue specimen blocks in preparation for routine slicing and microscope slide mounting. Another tool, the needle guide, permits the application of needle tracks at the interior of the tissue specimen which ensures accurate alignment of the histopathology tissue slices. Other tools include the use of standard imaging devices and annotation software, in which prepared microscope slides are digitally scanned, reviewed and annotated by a pathologist for diagnostic and orientation features.
In addition to providing the overall gross diagnosis for the entire specimen of the current pathology practice, the current invention provides a detailed histological analysis which, by applying image registration tools, can subsequently be mapped back to the digital imagery of the area of investigation. This reconstructed histopathology map will then provide the gold standard for colposcopy assessment and computer aided detection systems.
The current invention has the potential to raise the level of expertise of a more junior colposcopist to that of the more experienced colposcopist resulting in possible improvements in the identification of disease and early stage lesions. The invention could also reduce the diagnostic noise of inflammation and other conditions that interfere with the proper identification of pre-cancer and cancer, as well as minimizing the number of unnecessary biopsies.
By combining the objective accuracy of tissue classification using computer aided detection algorithms with the orientation properties of the tissue specimen processing of the current invention and digital slide annotations, each slide can be registered with its corresponding colposcopic image and show on a linear level where the disease is on the cervix and what level of disease is present. This has the potential to be able to direct a colposcopist to a more exact location for acquiring a biopsy. It could also provide a map for any follow-on surgical steps, enabling the physician to make smaller treatment excisions because the extent and location of the lesion can be determined more precisely.
The presently preferred embodiments of the invention described herein comprise a systematic framework for maintaining the spatial orientation of a three-dimensional tissue specimen removed from an area of investigation. The following patents and patent applications may be considered relevant to the field of the invention:
U.S. Pat. No. 1,859,467 to Rath, incorporated herein by reference, discloses means and methods for identifying products as to their particular origin, and which consists in making such structural changes in a product that it will possess a physical characteristic of any desired nature, and of a persistent kind, symbolic of a certain origin or derivation, to afford means for identifying the product with the producer, whether the latter is classed as a grower, manufacturer, processor, or seller thereof.
U.S. Pat. No. 2,868,072 to Weiskopf et al., incorporated herein by reference, discloses a mounting device for a paraffin-blocked histologic tissue specimen adapted for mounting to the specimen holder of a microtome.
U.S. Pat. No. 4,276,253 to Adler, Sr., et al., incorporated herein by reference, discloses a method for labeling a histological specimen, wherein such specimen is embedded in a paraffin block along with an integral set of supported elongated elements identifying such specimen for subsequent sectioning on a microtome. The identification elements are sectioned concurrently with the specimen, so as to form an integral part of the section.
U.S. Pat. No. 4,569,647 to McCormick, incorporated herein by reference, discloses an apparatus for the simultaneous preparation of multiple tissue specimens for histological examination, comprising cooperating stackable capsules, each of said capsules including a mold member and a complementary removable cover member.
U.S. Pat. No. 4,695,339 to Rada, incorporated herein by reference, discloses a system for preparing frozen tissue blocks for sectioning in a microtome. A vacuum-retracted membrane of plastic film material is used to draw a tissue block or specimen into planar contact with a polished platform that is positioned in a vacuum receptacle assembly.
U.S. Pat. No. 4,752,347 to Rada, incorporated herein by reference, discloses a method and apparatus for preparing a tissue block for sectioning in a microtome. A vacuum-retracted membrane of plastic film material is used to draw an underside of the tissue block or specimen into planar contact with a platform. The tissue block is frozen on the platform once it is properly oriented. The membrane is subsequently peeled away from the platform and O.C.T. compound is applied to the tissue blocks. The O.C.T. compound (after hardening) and the tissue block are transferred to a second platform carried by a mounting device such that the tissue underside is exposed. The tissue specimen is ready for sectioning as part of the Mohs fresh tissue surgical technique.
U.S. Pat. No. 4,893,424 to McLean, incorporated herein by reference, discloses a method and apparatus for permanently identifying an individual tissue sample sectioned for microscopic examination, as well as for identifying a tissue sample throughout the entire treatment cycle, including sectioning for mounting on slides.
U.S. Pat. No. 5,082,254 to Hunell et al., incorporated herein by reference, discloses a microtome object holder clamping assembly, having utility for positioning a ball-mounted specimen plate in a spatially fixed manner, but which is selectively repositionable by pivotal and/or rotational movement to dispose the specimen plate at any desired orientation relative to the microtome knife element. The microtome object holder clamping assembly of the invention may be usefully employed in a variety of microtome structures, including microtome cryostats, for sectioning of selected specimens.
U.S. Pat. No. 5,550,033 to Krumdieck, incorporated herein by reference, discloses a method and apparatus for preparing tissue samples for subsequent slicing in a microtome, utilizing a thermally transmissive body and removable mold heads to facilitate encapsulation of tissue samples in a gelatinous substance so that the samples may be selectively oriented for proper slicing in the microtome.
U.S. Pat. No. 6,017,476 to Renshaw, incorporated herein by reference discloses a specimen processing method which enables a specimen to be embedded in exactly the same plane as the cutting plane of a microtome during sectioning. This minimizes the number of sections required for histologic evaluation and eliminates the need for mechanical handling of the tissue specimen after its initial collection.
U.S. Pat. No. 6,387,653 to Voneiff et al., incorporated herein by reference, discloses an apparatus and method for producing tissue slides. The apparatus includes a holding assembly for manipulating the sample block, a blade assembly for preparing a thin section from the sample block, and a transfer roller mechanism for transferring the thin section to a receiving medium. The apparatus further includes a controller that may track the sample block and thin section.
U.S. Pat. No. 6,558,629 to Davidson, incorporated herein by reference, disclose a receptacle and dipping assembly aid in the preparation of a tissue sample for frozen histologic sectioning.
U.S. Pat. No. 7,005,110 to Taft et al., incorporated herein by reference, discloses a method to prepare tissue samples for sectioning comprising embedding a tissue sample in a porous embedding media in a desired orientation, followed by processing, and sectioning, all while being held in the porous embedding media. The post-tissue processing step of manual embedding in paraffin is eliminated from the process.
U.S. Pat. No. 7,029,615 to Lilischkis et al., incorporated herein by reference, discloses a method for the production of a material block containing a number of test samples, particularly tissue samples, a material blank, preferably made of paraffin and containing a number of openings to accommodate the corresponding tissue samples.
U.S. Pat. No. 7,168,694 to Bui et al., incorporated herein by reference, discloses a multi-axis chuck that rotates about at least two axes.
U.S. Pat. No. 7,257,953 to Rada, incorporated herein by reference, discloses apparatus and method for rapidly freezing tissue specimens at cryogenic temperatures that enhances heat transfer, quickly cools tissue holders and tissue, facilitates cutting of thin tissue sections, and facilitates tracking of tissue specimens throughout a tissue preparation and examination process.
U.S. Pat. No. 7,357,384 to Thiem, incorporated herein by reference, discloses a device for signaling the position of an orientable sample holder for a microtome.
U.S. Pat. No. 7,405,056 to Lam et al., incorporated herein by reference, discloses methods, devices, and systems using labeled punch tubes in the preparation of tissue microarrays and microarray slides, for tissue sample archiving, for correlating pathology, histology, and other biological test results with specific source tissues through intermediary tissue configurations.
U.S. Patent Application Number 2004/0018264 to Graziano et al., incorporated herein by reference, discloses a device and a method for sectioning of organs and irregular tissue blocks into tissue sections of a predefined thickness and orientation, in one uniform working process. The tissue is embedded into an alginate polymer, which is poured into an embedding container with two opposite arrays of parallel grooves. After hardening, the polymer is sectioned in slices of a predetermined thickness. This is achieved by razor blade cuts through an array of parallel grooves in the embedding container. The tissue and alginate polymer are then removed by removing the side of the embedding container, resulting in a series of parallel sections of predefined and often equal thickness.
U.S. Patent Application Number 2005/0112032 to McCormick, incorporated herein by reference, discloses a histological specimen retaining device for processing tissue, the device comprising: a foldable permeable sheet having edges; a permeable target disposed on the foldable permeable sheet within the edges of said sheet, thereby providing extended flap portions which flap portions are foldable to overlap the target; and a malleable securing strip attached to the foldable permeable sheet of a length sufficient to secure said folded flap portions overlapping said target.
U.S. Patent Application Number 2005/0112034 to McCormick, incorporated herein by reference, discloses a system for use in the preparation in situ of tissue specimens for histological examination. The invention also is directed to a method of processing a tissue sample for histological examination which does not require re-orienting the selected cutting plane in the specimen transfer step. Instead, the tissue sample remains oriented in a desired position throughout processing.
U.S. Patent Application Number 2007/0172942 to Walter et al., incorporated herein by reference, discloses an apparatus for producing a tissue array, the apparatus comprising: a donor block including tissue to be investigated, a specimen slide on which is provided a marked tissue section of the tissue to be investigated; a hollow needle for removing a sample from the donor block, and a sighting device connected to the hollow needle for positioning the hollow needle above the donor block.
U.S. Patent Application Number 2007/0184430 to Niendorf et al., incorporated herein by reference, discloses a method of analyzing a patient tissue sample to determine its diseased tissue fraction while essentially preserving the genomic and/or proteomic and/or epigenomic and/or biophysical properties of the tissue sample.
U.S. Patent Application Number 2007/0196891 to McCormick, incorporated herein by reference, discloses a histological specimen retaining device for processing tissue, the device comprising: a foldable permeable sheet having edges; a permeable target disposed on the foldable permeable sheet within the edges of said sheet, thereby providing extended flap portions which flap portions are foldable to overlap the target; and a malleable securing strip attached to the foldable permeable sheet of a length sufficient to secure said folded flap portions overlapping said target.
European Patent Number EP 1842044 to McCormick, incorporated herein by reference, discloses a system for use in the preparation in situ of tissue specimens for histological examination. The invention also is directed to a method of processing a tissue sample for histological examination which does not require re-orienting the selected cutting plane in the specimen transfer step. Instead, the tissue sample remains oriented in a desired position throughout processing.
Japan Patent Number JP 10333051 to et al., incorporated herein by reference, discloses a method to place a sample slice on a slide glass with reference at a sample slice positioning mark and to make a placing position definite by putting the sample slice positioning mark at the transparent part except the frost part of the slide glass.
International Patent Application PCT/AU1994/000715 to Muir et al., discloses a cassette for tissue specimen processing with removable top and bottom.
International Patent Application PCT/US1996/009676 to Casparian, incorporated herein by reference, discloses a method of optimizing gross tissue for pathological analysis, including positioning and orientation, comprising the steps of: contacting said tissue with a rigid, flat device, said device bearing on one surface at least one temperature sensitive adhesive component; and performing a pathological analysis
International Patent Application PCT/US2005/042933 to McCormick, incorporated herein by reference, discloses a system for use in the preparation in situ of tissue specimens for histological examination. The invention also is directed to a method of processing a tissue sample for histological examination which does not require re-orienting the selected cutting plane in the specimen transfer step. Instead, the tissue sample remains oriented in a desired position throughout processing.